1. Field of Invention
The present invention relates to an optimum gloss coated paper for improving toner adhesion and a method for forming an image on the optimized gloss coated paper. The gloss coated paper may be ideally used in apparatuses utilizing an electrophotographic process such as a copying machine, printer, facsimile and the like, especially in a color copying machine.
2. Description of Related Art
In an electrophotographic process, a fixed image is formed through a plurality of processes in which a latent image is electrically formed by various means on a photosensitive material utilizing a photoconductive substance. This latent image is developed using a toner and the toner latent image on the photosensitive material is transferred onto a transfer material, such as paper, to manifest a toner image. Then, this transferred image is fixed onto the paper. Recently, owing to the development of apparatuses and the spread of communication networks, electrophotographic processes are used not only in copying machines but also in printers.
For best results in forming an image, gloss coated paper is utilized in the printing process. Gloss coated paper is used most often when printing colors. Different types of gloss coated papers having different characteristics may be used to optimize the final print or copy, depending upon the type of imager being used. For example, caliper (thickness), stiffness, brightness, whiteness, and gloss are some properties that vary with different types of paper. The various combination of these and other properties, as well as other features including, for example, drying time, are considered when choosing an optimum paper for a specific imaging device such as a printer or copier.
More specifically, gloss coated printing papers are characterized by numerous physical and optical attributes. Some of the more critical properties of gloss coated printing papers include area density (grammage), thickness (caliper), surface topography (roughness), gloss, brightness, and ink absorption. To specify a paper having properties that meets all the requirements of a particular printing process as suitable, that is, having a suitable grade of paper, paper properties which contribute to performance and print quality must first be identified. (A grade of paper is a way of ranking paper by certain compositions and characteristics.) Furthermore, a desirable range of values for each of the paper properties must be specified for each selected property.
Determining a desirable range of values for each of the paper properties is typically performed by a trial and error process, sometimes taking over decades to develop. These papers have been developed in this manner for each successive development of printing technology. Examples include specific papers engineered for sheet-fed offset, web offset, gravure, flexo, ink jet, thermal transfer and xerographic printing processes. This successive trial and error process has resulted in each gloss coated paper having their own unique properties resulting in a range of image qualities. However, none of the paper properties of commercially available gloss coated papers have been identified and then optimized for increasing toner adhesion to improve image permanence.
A recent development in printing technology is Digital Color Production Printing (DCPP) using xerography. This refers to 4 or more color xerographic printing at process speeds exceeding 60 pages/minute. DCPP printers are used for commercial print applications, where they typically replace short to medium run offset presses.
The principal substrate used for DCPP, as in general for commercial printing, is coated paper. While there is a clear understanding of coated paper specifications for sheet and web offset printing, there has not been a specification developed for coated papers for xerographic DCPP.